The Experts below are selected from a list of 19320 Experts worldwide ranked by ideXlab platform
Qiuwang Wang - One of the best experts on this subject based on the ideXlab platform.
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study on local thermal hydraulic performance and optimization of zigzag type printed circuit heat exchanger at high temperature
Energy Conversion and Management, 2015Co-Authors: Lei Li, Xiangyang Xu, Yitung Chen, Qiuwang WangAbstract:Abstract High temperature heat exchanger is one of the most important components to transfer heat from the first loop to the second loop in the very high temperature reactor in Nuclear Energy Application. In order to enhance the heat transfer performance, a mini-channel heat exchanger called printed circuit heat exchanger has attracted more attention in recent years. In this paper, the thermal–hydraulic performance of zigzag-type printed circuit heat exchanger with helium as the working fluid operating at the typical temperature of 900 °C in the very high temperature reactor is studied. It is found that the flow and temperature at high temperature cannot achieve a fully-developed condition due to the significant variation of thermal physical properties arisen from the large temperature difference. However, the non-dimensional velocity and temperature can become steady after the second pitch and is similar to the fluid flow behaviors at low temperature. Therefore the local Nusselt number and friction factor at high temperature can match well with those at low temperature when the Reynolds number is bigger than 900. With the increase of inclined angle, the heat transfer and pressure drop increase. It is recommended to put the channel with a larger inclined angle to the cold region when using the hybrid channels. The heat transfer enhancement method with inclined angles completely depends on the operating conditions.
Muñoz López Carlos - One of the best experts on this subject based on the ideXlab platform.
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Revisión del potencial de ciclos de dióxido de carbono supercrítico aplicados a centrales Nucleares
2021Co-Authors: Muñoz López CarlosAbstract:Se ha realizado un estudio del diseño de sistemas principales y una simulación de Ciclos de potencia Brayton de CO2 supercrítico para su aplicación en reactores Nucleares de IV Generación. Se ha realizado el diseño y simulación de un ciclo Rankine de vapor para su aplicación en reactores Nucleares de IV Generación. El entorno de simulación utilizado es MatLab ©. El proyecto, consta en la primera parte de un análisis de los fundamentos, la historia y las principales aplicaciones de los ciclos de sCO2. En la segunda parte de un análisis del estado del arte (en cuanto a ciclos de sCO2 y a reactores Nucleares de IV Generación), un análisis de la oportunidad de aplicación de ciclos de sCO2 a reactores de IV Generación como los SFR, VHTR y GFR y finalmente una selección de un reactor Nuclear de referencia SFR y dos ciclos de sCO2 con condiciones de contorno específicamente seleccionadas. En la tercera parte, se presenta el procedimiento de resolución de los ciclos de sCO2 así como sus resultados numéricos, gráficas y análisis de sensibilidad, también el diseño de un ciclo Rankine de vapor con condiciones de contorno que permitan la comparación de resultados entre esta y los ciclos de sCO2. La simulación y la representación de datos se llevan a cabo con el uso del software MatLab© y MiniRefProp©. Los códigos, disponibles en los anexos, son una imagen de los fundamentos teóricos y metodológicos que se desarrollan a lo largo del trabajo y que permiten cálculos iterativos necesarios para la determinación numérica de los ciclos. Se desarrollan aproximaciones más exactas mediante el uso de la metodología Nellis & Klein para el cálculo del punto de “pinch”. Los resultados obtenidos son lógicos y coherentes con investigaciones anteriores como la de Vaclav Dostal [1] o Yoonhan Ahn et al, [2]. Para una potencia de 600 MW, temperatura máxima de 500 ºC y temperatura mínima de 32 ºC el ciclo de sCO2 de recompresión resulta más eficiente que el simple con recuperación, 41,8 % frente a 36,85 %. No obstante, el ciclo de Rankine con mismas condiciones de contorno obtiene una eficiencia térmica mayor, del 43,32 %. Reactores de IV Generación como los SFR se pueden emparejar de manera satisfactoria con ciclos de conversión de potencia de sCO2 como el de recompresión o simple con recuperación. En general, se puede afirmar que en lo que a este estudio respecta, se ha demostrado el futuro potencial del ciclo de recompresión de CO2 supercrítico en su aplicación a energía Nuclear, aunque un análisis de optimización tecno-económico sería necesario para comprobar si el ciclo de recompresión, a pesar de tener menor eficiencia, seguiría siendo viable frente al ciclo convencional Rankine.A study of the design of main systems and a simulation of supercritical CO2 Brayton power cycles have been carried out for its Application in Generation IV Nuclear reactors. The design and simulation of a steam Rankine cycle has been performed for its Application in Generation IV Nuclear reactors. The simulation environment used is MatLab ©. The project consists in the first part of an analysis of the fundamentals, history, and main Applications of the sCO2 cycles. In the second part, an analysis of the state of the art (in terms of sCO2 cycles and Generation IV Nuclear reactors), an analysis of the opportunity to apply sCO2 cycles to Generation IV reactors such as SFR, VHTR and GFR and finally a selection of a reference SFR Nuclear reactor and two representative cycles of sCO2 with specifically selected boundary conditions. In the third part, the resolution procedure of the sCO2 cycles is presented as well as its numerical results, graphs, and sensitivity analysis, also the design of a Rankine steam cycle with boundary conditions that allow the comparison of results between this and sCO2 cycles. Simulation and data representation are carried out with the use of MatLab © and MiniRefProp © software. The codes, available in the annexes, are an image of the theoretical and methodological foundations that are developed throughout the work and that allow iterative calculations necessary for the numerical determination of the cycles. More exact approximations are developed by using the Nellis & Klein methodology to calculate the pinch point. The results obtained are logical and consistent with previous research such as that of Vaclav Dostal [1] or Yoonhan Ahn et al, [2]. For a power of 600 MW, a maximum temperature of 500 ºC and a minimum temperature of 32 ºC, the recompression sCO2 cycle is more efficient than the simple recuperated, 41.8% versus 36,85%. However, the Rankine cycle with the same boundary conditions obtained a higher thermal efficiency of 43.32%. Generation IV reactors such as SFRs can be successfully coupled with sCO2 power conversion cycles such as recompression or simple recuperated. Overall, it can be stated that as far as this study is concerned, the future potential of the supercritical CO2 recompression cycle in Nuclear Energy Application has been demonstrated, although a technoeconomic optimization analysis would be necessary to check whether the recompression cycle, despite have lower efficiency, it would still be viable compared to the conventional Rankine cycle.Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriale
Lei Li - One of the best experts on this subject based on the ideXlab platform.
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study on local thermal hydraulic performance and optimization of zigzag type printed circuit heat exchanger at high temperature
Energy Conversion and Management, 2015Co-Authors: Lei Li, Xiangyang Xu, Yitung Chen, Qiuwang WangAbstract:Abstract High temperature heat exchanger is one of the most important components to transfer heat from the first loop to the second loop in the very high temperature reactor in Nuclear Energy Application. In order to enhance the heat transfer performance, a mini-channel heat exchanger called printed circuit heat exchanger has attracted more attention in recent years. In this paper, the thermal–hydraulic performance of zigzag-type printed circuit heat exchanger with helium as the working fluid operating at the typical temperature of 900 °C in the very high temperature reactor is studied. It is found that the flow and temperature at high temperature cannot achieve a fully-developed condition due to the significant variation of thermal physical properties arisen from the large temperature difference. However, the non-dimensional velocity and temperature can become steady after the second pitch and is similar to the fluid flow behaviors at low temperature. Therefore the local Nusselt number and friction factor at high temperature can match well with those at low temperature when the Reynolds number is bigger than 900. With the increase of inclined angle, the heat transfer and pressure drop increase. It is recommended to put the channel with a larger inclined angle to the cold region when using the hybrid channels. The heat transfer enhancement method with inclined angles completely depends on the operating conditions.
Isamu Yasuda - One of the best experts on this subject based on the ideXlab platform.
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synergistic production of hydrogen using fossil fuels and Nuclear Energy Application of Nuclear heated membrane reformer
Nuclear Science, 2004Co-Authors: Masao Hori, Kazuaki Matsui, Masanori Tashimo, Isamu YasudaAbstract:Processes and technologies to produce hydrogen synergistically by the steam reforming reaction using fossil fuels and Nuclear heat are reviewed. Formulas of chemical reactions, required heats for reactions, saving of fuel consumption or reduction of carbon dioxide emission, possible processes and other prospects are examined for such fossil fuels as natural gas, petroleum and coal...
Xiangyang Xu - One of the best experts on this subject based on the ideXlab platform.
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study on local thermal hydraulic performance and optimization of zigzag type printed circuit heat exchanger at high temperature
Energy Conversion and Management, 2015Co-Authors: Lei Li, Xiangyang Xu, Yitung Chen, Qiuwang WangAbstract:Abstract High temperature heat exchanger is one of the most important components to transfer heat from the first loop to the second loop in the very high temperature reactor in Nuclear Energy Application. In order to enhance the heat transfer performance, a mini-channel heat exchanger called printed circuit heat exchanger has attracted more attention in recent years. In this paper, the thermal–hydraulic performance of zigzag-type printed circuit heat exchanger with helium as the working fluid operating at the typical temperature of 900 °C in the very high temperature reactor is studied. It is found that the flow and temperature at high temperature cannot achieve a fully-developed condition due to the significant variation of thermal physical properties arisen from the large temperature difference. However, the non-dimensional velocity and temperature can become steady after the second pitch and is similar to the fluid flow behaviors at low temperature. Therefore the local Nusselt number and friction factor at high temperature can match well with those at low temperature when the Reynolds number is bigger than 900. With the increase of inclined angle, the heat transfer and pressure drop increase. It is recommended to put the channel with a larger inclined angle to the cold region when using the hybrid channels. The heat transfer enhancement method with inclined angles completely depends on the operating conditions.
